Demand of a liquid crystal display has been increased in the use for a liquid crystal television, a liquid crystal display of a personal computer, and the like. In general, a liquid crystal display is constituted of a liquid crystal cell that is obtained by sandwiching a transparent electrode, a liquid crystal layer, a color filter and the like by glass plates, and two polarizing plates arranged on both sides of the liquid crystal cell, and each of the polarizing plates has a constitution in which a polarizer (also referred to as a polarizing film) is sandwiched between two films (protective films for a polarizing plate).
As the liquid crystal display, some drive systems of a TN type (Twisted Nematic type), an IPS type (In-Plane Switching type), an OCB type (Optically Compensated Bend type), a VA type (Vertical Alignment type), and the like have been known. Among them, a VA type liquid crystal display can obtain an excellent viewing angle characteristic, and high contrast, therefore has been receiving attention in recent years. However, in a VA type liquid crystal display, there is a problem that the brightness change and color change due to viewing angle are large, caused by the arrangement method of the liquid crystal molecule, and the way of motion of the liquid crystal molecules at the time of application of voltage.
For this problem, it has been reported that the arrangement of an optically biaxial optical film between a polarizing plate and a liquid crystal layer of a liquid crystal display is effective. In Japanese Patent Application Laid-Open (JP-A) No. 2009-288816, an invention relating to a liquid crystal display in which an optical compensation sheet is bonded above and below the liquid crystal cell in VA mode, a polarizing film is arranged above and below the optical compensation sheet, and a protective film is arranged above and below the polarizing film is described. According to JP-A No. 2009-288816, it is described that an intended retardation value is achieved by using a cellulose-lower fatty acid ester film containing a predetermined compound as the optical compensation sheet (optical film), and application to a VA type liquid crystal display can suitably be performed.
By the way, as the optical film, various ones have been reported so far. For example, in Japanese Patent No. 5047784 (specification of U.S. Application Publication No. 2009/273837), a phase difference film (optical film) containing cellulose ester that has a predetermined structure and a predetermined molecular weight, and cellulose ester or cellulose ether that has a predetermined structure and a predetermined molecular weight, in an amount of 20 to 50% by weight, and in an amount of 80 to 50% by weight, respectively has been reported. According to Japanese Patent No. 5047784, it is described that the predetermined retardation, and the durability against the temperature change and the like are both satisfied by the inclusion of cellulose ester, and further predetermined cellulose ester or cellulose ether having a molecular weight different from that of the above-described cellulose ester. However, when the technique described in Japanese Patent No. 5047784 was checked, the film was easily torn during the production and transport of a film and during the cutting because of the low tear strength, and had a problem in the handleability.